Stabilizer system



June 5, 1934.

M. MORRISON STABILIZER SYSTEM Filed June 50, 1931 r 7 L INVENTOR M/WFWDL50 r BY 9 42 ATTORNEY Patented June 5, 1934 UNITED STATES PATENT?OFFICE STABILIZER SYSTEM poration of Delaware Application June 30, 1931,Serial No. 547,891

5 Claims.

My invention relates to stabilizing systems and has particular referenceto such systems utilized with discharge devices, such as X-ray tubes andthe like, in which the operation is dependent upon thermionic cathodes.

In such systems it is customary to apply a potential between theelectrodes of the device and tosupply a heating current to the cathode.The electrical energy for this purpose is usually obtained from a sourceof alternating current potential which is subject to fluctuations and ifnot in some manner compensated for erratic fiow results in the dischargedevice.

In order to prevent these supply source fluctuations from influencingthe discharge circuit and causing a variation in the flow of currentbetween the electrodes of the discharge device one controlling factor isthat of maintaining the cathode heating current constant therebyprecluding any variation in the temperature of the cathode. Otherfactors which tend to cause variations in the discharge current are alsoof major importance, such for example, as variations in the dischargecircuit caused by gaseous ionization within the discharge device. Thereare other factors which likewise may affect the constancy of flow of thedischarge current, but by controlling the above noted factors a degreeof stabilization is obtained that renders all of the causes tending tovary this flow of infinitesimal consequence.

If the cathode heating current and consequently the temperature of thecathode is varied inversely to variations in the discharge circuit,regardless of the particular factor tending to cause such variation, thedischarge current can be maintained constant without these factorsinfluencing the discharge current to any appreciable extent.

It is accordingly an object of my invention toprovide a system forstabilizing current in a thermionic discharge device by maintaining thethermionic emissivity of the cathode constant under all conditions ofoperation.

Another object of my invention is the provision of a stabilizer systemfor a thermionic discharge device in which the temperature of thecathode is varied in accordance with variations in the source of supply.

A further object of my invention is the provision of a stabilizer systemfor thermionic discharge devices in which the thermionic emissivity ofthe cathode is varied in accordance with variations in the dischargecircuit to thus maintain the current flowing through the deviceconstant.

Still further objects of my invention will become apparent to thoseskilled in the art by reference to the accompanying drawing wherein Fig.l is a diagrammatic illustration of a circuit for energizing athermionic discharge device embodying the features of my invention; and

Fig. 2 is a diagrammatic illustration of the same circuit showing amodification of my device.

Referring now to the drawing in detail I have shown in the figures asource of alternating current potential, such as conductors L1 and L2. Alow tension transformer 5 has its primary winding 6 connected to thissource of supply L1 and L2 and a high tension transformer 7 likewise hasits primary winding 8 connected to the supply conductors L1 and L2 bymeans of conductors 9 and 10.

The secondary winding 12 of the low tension transformer 5 is connectedto the cathode 13 of a thermionic discharge device it by means ofconductors l5 and 16. The secondary winding 17 of the high tensiontransformer 7 is connected by means of conductors 18 and 19 to a pair ofterminals 2c and 22 of a high tension rotary rectifier 23 which isdriven by a synchronous motor (not shown) This rectifier is providedwith a pair of toroidal surfaces 24 and 25.

Another pair of terminals 26 and 27 of the rectifier are provided and aconductor 28 extends from the terminal 27 to the anode 29 of thedischarge device 14. A conductor 30 extends from the terminal 26 to awinding 32 of an impedance device having an iron core of substantial Ushape 33. The other end of the winding 32 is connected to a secondwinding 34 by means of a conductor 35 which is likewise wound uponanother leg of the iron core 33. This latter winding 34 is connected inseries with the conductor 16 extending from the secondary winding 12 ofthe low tension transformer 5 to the cathode 13.

An armature 36 is provided for the impedance device and is tensioned bymeans of a coil spring 37 which is readily secured to a fixed location38 by means of an adjustable connection, such as a stud 39 and nuts 40.

Referring now more particularly to Fig. 2 the structure therein showndiffers from that shown in Fig. 1 in that an impedance device 42 havingan iron core of substantially U shape is provided with a winding 43which is connected with the conductor 30. A similar impedance device 14:having an iron core is provided with a winding 45 in series with theconductor 16.

It is readily apparent that in this modification the impedance deviceswith their respective windings are independent of one another instead ofbeing wound upon the same core as previously described.

An elongated armature 46 extends across both of the impedance devices 42and 44 and is pivoted at 47. One end of this armature is tensioned bymeans of the adjustable coil spring 37 in the same manner as thearmature 36 shown in Fig. 1. The other end of the armature 46 is dampedby means of a suitable device such as a fixed lug 48 which preventsvibration of the armature.

The operation of my device is as follows: Current being supplied to theprimary windings 6 and 8 of the respective transformers 5 and '7 fromthe supply conductors L1 and L2 will induce a current in the respectivesecondary windings 12 and 17 of these transformers. The secondarywinding 12 of the low-tension transformer 5 will supply heating currentto the cathode 13 of a discharge device 14 by means of conductors 15 and16. The secondary winding 17 of the transformer 7 will supply a hightension current to the terminals 20 and 22 of the rectifier 23 by meansof the conductors 18 and 19. The rectifier 23 being rotated by asynchronous motor (not shown) will cause its toroidal surfaces 24 and 25to rotate therewith and will establish during its rotation a connectionbetween the terminals 20 and 22, and 26 and 2'7, as shown in Figure 1.

At this time, however, no current will flow to the discharge device 14as no circuit is established from the secondary winding. When, however,the rectifier makes a quarter of a revolution to the position shown inFig. 2, the toroidal surface 24 will establish a connection between theterminals 20 and 26 and the surface 25 will establish a connectionbetween the terminals 22 and 27.

At this time high tension current will flow to the discharge device 14in the following manner; from the secondary winding 17 by means ofconductor 18 to the terminal 20, the toroidal surface 24 to the terminal26, through conductor 30 to the impedance winding 32 by means ofconductor 35 to the other impedance winding 34 to conductor 16 to thecathode 13, anode 29, through conductor 28 to the terminal 27 thencethrough the toroidal surface 25 to the terminal 22 and back to thesecondary winding 17 by means of conductor 19.

It is readily apparent that this circuit is completed only duringalternate half waves of the alternating current cycle by means of therectifier device 23 and its toroidal surfaces 24 and 25. During theremaining half waves of the cycle the current induced in the secondarywinding 17 will be prevented from passing by means of the rectifierdevice.

The armature 36 of the impedance device being adjusted by means of thenuts 40 for the amount of current desired need not be further disturbed.Assuming now that the current in the impedance winding 34, which is inseries with the cathode 13, rises due to voltage fluctuations in thesource of supply, whi h is induced in the secondary winding 12, thearmature 36 will be attracted by the magnetic force set up or created bythe winding 34 and will then permit the magnetic flux of the impedancedevice to pass through the armature 36.

The foregoing action of the armature increases the impedance of winding34 and reduces the amount of current flowing through the winding 34,which likewise reduces current supplied to the cathode 13, consequentlyreducing the temperature thereof.

In the same manner should the current flowing in the discharge circuitincrease due to gaseous ionization within the discharge device 14 orfrom any other factor the armature 36 will again be attracted to thecore 33 of the impedance device by the current flowing through thewindings 32 and a portion of the impedance winding 34. This again willalter the magnetic flux of the impedance device by attracting thearmature 36 and increase the impedance of the Winding 34 which is inseries with the cathode 13. The increase of impedance of winding 34decreases the current fiowing to the cathode thus reducing thetemperature and the thermionic emissivity of the cathode.

It is to be understood that the action of the armature 36 in varying theimpedance of the filament heating circuit and the discharge circuittakes place due to variations in the source of supply or the dischargecircuit during the cycle in which current is permitted to flow in thedischarge circuit by the rectifier device 23.

When the rectifier device is in the position shown in Fig. 1 and currentis prohibited from flowing due to the circuit to the discharge devicebeing opened by the rectifier device, the spring 37 will retract thearmature from the core 33 of the impedance device, the action,therefore, of the core would be that of a vibrator responsive to anincrease of current in the impedance windings 32 and 34 above apredetermined amount.

The operation of the system shown in Fig. 2 is in most respects similarto that of the impedance device just described with the exception thatthe armature 46 is prevented from vibrating by the damper 48. In thismodification the spring 37 is adjusted for the amount of current desiredand when the current flowing through either of the windings 43 or 45exceeds this amount the armature will be slightly rotated about itspivot 47 to thus vary the magnetic flux of the respective iron cores 42and 44. Likewise in this modification the varying of the magnetic fluxreduces the amount of current flowing in the winding 45 and againdecreases the temperature and electron emissivity of the cathode.

The armature 46 where it engages the damper 48 is provided with aportion which is slightly flexible to enable a slight rotation of thearmature about its pivot but sufficiently tensions the armature toprevent vibration.

It can, therefore, be readily seen that I have provided a stabilizersystem in which the temperature and electron emissivity of the cathodemay be readily varied inversely to fluctuations in a source of supplyand to variations in the discharge circuit due to gaseous ionizationwithin the device, or any other factors tending to vary the dischargecurrent.

Although I have shown and described several embodiments of my device Ido not desire to be limited thereto as various other modifications ofthe same may be made without departing from the spirit and scope of theappended claims.

What is claimed is:

1. The combination with an electron discharge device having a cathode tobe heated, of a high tension transformer for supplying energy to theelectrodes of said devices, a low-tension transformer for supplyingheating current to the oathode of said device, a source of supplysubject to fluctuations for energizing both said transformers, and aninductance element provided with a winding in series with the electrodesof said device and a second winding in series with the cathode of saiddevice for causing variations in said source and variations in currentsupplied by said high tension transformer, to maintain the currentsupplied to the electrodes of said device constant.

2. The combination with an electron discharge device having a cathode tobe heated, of a high tension transformer provided with a secondarywinding for supplying energy to the electrodes of said device, alow-tension transformer provided with a secondary winding for supplyingheating current to the cathode of said device, a source of electricalsupply subject to fluctuations common to the primary windings of bothsaid transformers, and an inductance element provided with a windingconnected in series with the secondary winding of said high tensiontransformer, and a second winding connected in series with the secondarywinding of said low tension transformer, said inductance elementwindings being inductively related to each other to cause a variance inthe current supplied to the cathode inversely to the fluctuations insaid source of supply and to variations in current supplied by said hightension transformer for maintaining the current supplied to theelectrodes of said device constant.

3. The combination with an electron discharge device having a cathode tobe heated, of a high tension transformer provided with a secondarywinding for supplying energy to the electrodes of said device, alow-tension transformer provided with a secondary winding for supplyingheating current to the cathode of said device, a source of electricalsupply subject to fluctuations common to the primary windings of bothsaid transformers, an impedance device comprising a winding in serieswith the electrodes of said device, and the secondary of said hightension transformer, a second winding in series with the cathode of saiddevice and the secondaryof said low tension transformer, an armature forsaid impedance device, operable in response to the current flowing inboth of said windings, for varying the magnetic flux of said impedancedevice to cause a variance in the current supplied to the cathode ofsaid device, inversely to variations in said supply source and tovariations in current supplied by the secondary winding of said hightension transformer to said device to maintain the current supplied tothe electrodes of said device constant.

4. The combination with an electron discharge device having a cathode tobe heated of a high tension circuit including a high tension transformerprovided with a secondary winding, for supplying energy to theelectrodes of said device, a low tension circuit including a low-tensiontransformer provided with a secondary winding for supplying heatingcurrent to the cathode of said device, a source of electrical supplysubject to fluctuations common to the primary windings of both saidtransformers, an impedance device comprising a winding in series withthe electrodes of said device and the secondary of said high tensiontransformer, a second winding in series with the cathode of said deviceand the secondary of said low tension transformer, a vibrating armaturefor said impedance device operable in response to the current in both ofsaid windings, for varying the magnetic flux of said impedance deviceand altering the impedance of one of said circuits inversely tovariations in the other of said circuits and said source of supply tomaintain the current supplied to the electrodes of said device constant.

5. The combination with an electron discharge device having a cathode tobe heated, a main energizing circuit for supplying high tension currentto the electrodes of said device, a low tension circuit for heating thecathode of said device, a source of alternating current subject tofluctuations for supplying energy to both of said circuits, aninductance element provided with a winding in series with the electrodesof said device, an inductance element provided with a winding in serieswith the cathode of said device, an armature common to both of saidinductance elements responsive to the current in said high and lowtension circuits for varying the impedance of both of said circuits andvarying the current in said low tension circuit inversely to variationsin said ,g

high tension circuit and said source for maintaining the currentsupplied ,to the electrodes of said device constant.

MONTFORD MORRISON.

